append can take an improper list at the final argument (both R7RS and
SRFI-1 explicitly allows it). For valid indexes, `(take xs i)` and
`(drop-right xs i)` never return improper lists, so I think both examples
are valid.
On Mon, Sep 1, 2025 at 5:11 PM Peter McGoron wrote:
> The description o
> append can take an improper list at the final argument (both R7RS and
> SRFI-1 explicitly allows it). For valid indexes, `(take xs i)` and
> `(drop-right xs i)` never return improper lists, so I think both
> examples are valid.
I see, I am incorrect there.
The take-right and drop-right exampl
The description of take-right and drop-right reads
For a legal i, take-right and drop-right partition the list in a
manner which can be inverted with append:
(append (take flist i) (drop flist i)) = flist
This example is a duplicate of take and drop .In addition, both examples
ar
On Tue, Sep 2, 2025 at 3:59 AM Peter McGoron wrote:
> The take-right and drop-right example still uses `take` and `drop`
> instead of `take-right` and `take-drop`, so it should be modified to
>
> (append (drop-right flist i) (take-right flist i)) = flist
>
Thanks. Fixed, noted in errata,
